zulu.861.climate
Kushisa kakhulu
Ososayensi bakhiphe isexwayiso esinzima: sokuthi umhlaba njengamanje uyafa ngenxa yokungaqapheli kwabantu bejahe imali. Uma kungekho okwenziwayo ngalokhu ngokushesha, sizobhekana nezinkinga ezizokwenza i-AIDS ibhebhetheke ngokungenamkhawulo...
UKUSHISA kuxakile emhlabeni ngenxa yentuthu kawoyela. Ukufunda ngokushintsha kwesimo sezulu kubandakanya ucwaningo lwezinto eziningi. Okutholakalayo kucace bha kodwa kwethusa kakhulu: usuku ngosuku, umzuzu ngomzuzu, SIBULALA UMHLABA.
Umhlaba uyashisa ngenxa yentuthu engama-gas ekhishwa yizimoto, izitshalo nezinye izinto. Lokhu kwenza i-gas yakhele emkhathini ngaphezu komhlaba.
Umphumela walokhu kungaba yisibhicongo. Kumanje lezi zinto siyazibona zenzeka - kusho kwexwayisa imibiko yakamumva yabe-Intergovernmental Panel On Climate Change (IPCC), okuyiqembu lososayensi abangu-2 500 abahlanganiswa ndawonye ngabe-United Nations.
Uma abantu ubabuza ngesimo sokushintsha kwezulu, bavele bathi, "Yinto engeke ngisayibona ngoba ngiyobe sengifile." - njengamanje, ngokusho kukaPieter Tans ongumcwaningi kwabeNational Oceanic And Atmospheric Administration eMelika, sibhekene nezinguquko ezizokwenzeka kulesi sikhathi esiphila kusona.
UStephen Mwakifwamba weCentre For Energy, Environment, Science And Technology eTanzania ngomunye wabacwaningi abakuvumile lokhu.
"Esikhathini esedlule, sasiba nesomiso cishe eminyakeni elishumi kodwa manje yinto esingazi ukuthi izokwenzeka nini ngoba yenzeka njalo, kanjalo futhi nezikhukhula.
"Isimo sezulu akulula ukusiqagula. Kungenzeka sibe nezikhukhula ngoMay noma isomiso njalo eminyakeni emithathu. Ezindaweni eziphakeme, ezazingahlushwa omiyane, sebekhona.
"Amazinga amanzi ayehla nsuku zonke. Izimvula zifika ngezikhathi ezingeyizo kubalimi nokuyinto eholela ezinkingeni eziningi."
Amazinga esimo sezulu esijwayelekile kungenzeka anyuke ngokungu-6,4°C ngasekupheleni kwale-century, ngokusho kombiko wabe-IPCC.
Ngabe kwenzekani?
Le nkinga eyaziwa ngokuthi yi"greenhouse effect" yatholwa nguJoseph Fourier ngo-1824. Ama-gas amaningi adala lokhu, yiwo enza ukushisa kwedlulele emhlabeni.
Ngaphandle kwale-greenhouse effect amazinga okushisa angehla ngo-30°C.
Ama-gas amakhulu yilawo angumhwamuko wamanzi adala amaphesenti angu-36-70 (awabandakanyi amafu); carbon dioxide (amaphesenti angu-9-26); methane (amaphesenti angu-4-9); ne-ozone (amaphesenti angu-3-7).
Kodwa izimboni zemisebenzi, izimoto, amabhanoyi nezinye izinto ezenziwa abantu yikho osekukhuphule izinga le-carbon dioxide ne-methane emkhathini.
Imvelo ayikwazi ukumelana nalokhu okulokhu kuqhubeka kukhula. Esikhundleni sokugcina umhlaba ushisa ngokwanele ukuze siphile, lawa ma-gas achaza ukuthi umhlaba uya ngokuba ushisa...
Iminyaka emihlanu eyashisa kunayo yonke emlandweni isukela ngo-1997, kanti u-2005 yiwo owashisa kunayo yonke iminyaka emlandweni.
Ezinye zezinto esingazilindela uma kungekho okwenziwayo ukulungisa lesi simo...
AMAQHWA ANCIBILIKAYO
Emhlabeni ubungako bamatshe ayiqhwa sekunciphe ngamaphesenti angu-50 kusukela ekupheleni kwe-19th Century. Kusukela ngo-1980 lokhu kuncibilika bekulokhu kuqhubeka.
Ngo-March 2005, ukwenza isibonelo, iqhwa ebeliphezu kwezintaba iMount Kilimanjaro iminyaka engu-11 000 selashabalala.
Umphumela? Lokhu akudali izikhukhula nokuguguleka kwezindawo, kodwa kubeka nezinye izindawo engozini.
Amanzi atholakala ngokuncibilika kwamadwala amaqhwa, angenela emifuleni nabantu bakwazi ukuwasebenzisa. Ekupheleni kwalawa madwala, amanzi "ayasha".
Lokhu sekuyabonakala ezindaweni zaseHimalaya, nokuyilapho ukuncibilika kwalokhu kusho ukuthi ezinye izindawo, kungenzeka zingabi nawo amanzi.
UKUGCWALA KOLWANDLE
Ngesikhathi umhlaba ushisa, umthamo wolwandle uyakhula nokuchaza ukuthi amanzi afudumele athatha indawo enkulu kunalawo abandayo. Ukuncibilika kwamaqhwa amakhulu kwengeza amanzi amaningi olwandle.
Kucatshangelwa ukuthi umthamo wolwandle ungakhuphuka cishe ngo-59cm eminyakeni engu-100 elandelayo.
Umphumela? Zonke izindawo eziseduze kolwandle ziyokhukhuleka, eziningi zibe yiziqhingi. Lokho kusho ukuhamba kweTheku, iCape Town ne-East London kanjalo nezindawo ezifana neNew York, Tokyo, Hong Kong neCalcutta.
Lokhu kwaqala ukwenzeka ngoDecember 2006 lapho kucwila isiqhingi saseLohachara eSundarbans eBay of Bengal nokwadingeka ukuba abantu ababalelwa ku- 10 000 baye kwezinye izindawo. I-IPCC ithi abantu ababhacisiwe ngenxa yalesi simo, bayobe bebalelwa ku-150 million ngonyaka ka-2050.
ISOMISO ESIDALA UKUSHISA
Ukwenyuka kwamazinga okushisa kukhuphula umswakama osuka ezweni nasemanzini uholele ekutheni kube khona isomiso ezindaweni eziningi. Izindawo ezinesomiso yizona ezikhukhuleka ukwedlula ezinye uma izulu lina.
Umphumela? Kumanje sesiqalile ukubona umphumela walokhu e-Africa nokuyilapho isomiso sithatha isikhathi eside, senze umonakalo omkhulu kwezolimo nasezimpilweni zabantu.
IZIKHUKHULA EZINKULU
Imimoya nezikhukhula kuthola amandla ako emanzini afudumele. Uma amazinga okushisa ekhuphuka, izikhukhula ziba namandla.
Umphumela? Imimoya enamandla nezikhukhula kuyadlanga, kube ngokwesikhathi eside kudale umonakalo omkhulu.
Emhlabeni inombolo yomkhakha u-4 no-5 wemimoya enamandla - leyo enesivinini esingaphezu kuka-56 metres ngomzuzwana - sekukhuphukile kusuka kumaphesenti angu-20 eminyakeni yo-1970 kuya kumaphesenti angu-35 eminyakeni yo-1990.
Ngo-April 2004, isivunguvungu sokuqala e-Atlantic esenzeka, sashaya iBrazil ngemimoya yesivinini esingu-144 km/h. Ngo-January 2007, i-United Kingdom nenyakatho ye-Europe nazo zahlaselwa yimimoya enamandla - nokuyisimo sezulu esingajwayelekile kulezo zindawo.
IZIFO EZININGI
Ukushintsha kwesimo sezulu kuzokhuphula izinga lokubhebhetheka kwezifo ezithathelanayo, ikakhulu ngenxa yamazinga afudumele anika izinambuzane ezithwala amagciwane amandla okusabalalisa izifo.
Umphumela? Izifo nezilokazana ezifana nomiyane ezithwala i-malaria, zingakwazi ukuthola ukunethezeka ezindaweni ezazibanda zingakwazi ukuphila kuzo.
BONA ZULU - May 2007
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Siyawubulala umhlaba
IQINISO: IMelika inamaphesenti amahlanu abantu emhlabeni wonkana, kodwa inamaphesenti angu-22 okukhipha i-carbon okuyiyo edala ukushisa emhlabeni.
BONA ZULU - May 2007
Iminyaka emihlanu eyashisa kakhulu emlandweni yenzeka kusukela ngo-1997, kanti u-2005 kwaba ngunyaka owashisa kunayo yonke empilweni.
IQINISO: Sekutholakale utshani okokuqala ngqa e-Antarctica.
IQINISO: I-Golden Toad yaseCentral America kucatshangelwa ukuthi yizilwane zokuqala ukuba ziphele ngenxa yokushintsha kwesimo sezulu. Zanyamalala ngo-1999.
14 BONA ZULU - May 2007
IQINISO: Ngenxa yokuncibilika kweqhwa e-Artic, amabhele akuleyo ndawo kungenzeka aphele emhlabeni esikhathini esingaphansi kweminyaka engu-100.
Ucwaningo olwenziwa kabili ngo-2002 lwathola ushintsho olukhulu ezitshalweni nasezilwaneni. Ezine kwezinhlanu izilwane iya ngokushintsha indlela yendalo yazo yokuphila .
Kwatholakala futhi ukuthi amaxoxo ayephefumula, izimbali ziqhakaza, izinyoni zindize zihambe ezindaweni zazo izinsuku ezimbili ngaphambi kwesikhathi, njalo eminyakeni elishumi.
Kwenzeka ushintsho
Konke kusemahlombe amabhizinisi amakhulu. "Sesehlise ukukhishwa kukawoyela wethu ngamaphesenti cishe angu-75," kusho uJerry Mahlman, ongusosayensi wesimo sezulu kwabeNational Centre For Atmospheric Research (NCAR).
Labo woyela babandakanya, uphethiloli namalahle. Lokhu kusetshenziswa kuyo yonke imishini, kusukela ezimotweni nasemabhanoyini kuye ezimbonini ezinkulu zemisebenzi.
Labo woyela bakhipha ama-gas okuyiwo adala ukushisa emhlabeni (i-global warming).
Kuncane kabi esingakwenza ngalesi simo. "Lokhu akuyona into efana 'nokuvuselelwa kwezinto esezisebenzile'," kusho uMahlman.
Umphakathi wamazwe omhlaba kufanele usebenze ngokubambisana ukuze ulwe nale nkinga yokushisa emhlabeni, ngokusho kochwepheshe. Isikhathi siya ngokuphela. Ngisho nokwenyuka kwezinga lokushisa ngo-2,4°C eminyakeni engu-50 ezayo kuthathwa njengengozi enkulu kakhulu.
"Uma silinda isikhathi eside, izinkinga zizokwedlulela kakhulu," kusho uGerald Meehl we-NCAR's Gerald Meehl. [z]
Yini engenziwa?
BONA ZULU - May 2007 15
